Ha Full Disk - 9th July

[markt]

I had initially decided to have a go at doing a full disk mosaic using my new 2.5xTV powermate, however something is not quite square in my system, and as a result the images were plagued with Newtons Rings. I had decided to test out the flat field theory today and for the powermate series this was effective in removing just about all traces of the rings, unfortunately todays seeing didn't want me to work at near f26, and the resulting images were a bit soft and mushy.

Sooo, I switched down to the 2x barlow, which also gives me newtons rings, took my run for the flat image then set about to get the frames for the mosaic... I was really pleased with the outcome - newtons rings completely gone! I do think the image shows better detail when I looked back at previous images with the same optical setup but taken not using a flat frame... The barlow displays slight darkening towards the periphery of the edge of individual panes which can be seen as it affects the seams in the mosaic. I'm hoping a meade 2x tele-extender will help rectify this...

Anyway, enough of my rambling, here's todays pic >>>

ha full disk f20 by Mark Townley, on Flickr

I have more data to process still, however me thinks that may well be a job for tomorrow.

Hope you like the image!

Mark

[Photosbykev]

beautiful image a standard for me to aim at.

[markt]

Thanks Kev, appreciate the kind words

I think I prefer the black and white for this particular image - to me the colour seems to hide some of the finer detail...

ha full disk b&w by Mark Townley, on Flickr

What's everybody elses preference - colour or black and white?

[Cordulegaster]

They are both excellent. I prefer the colour but I see what you mean about the detail.

Glyn

[Merlin66]

Colour for "show and tell" - B&W for analysis.

BTW Newton rings can be caused by the cover plate on the CCD chip. Nick H. a couple of years ago did some investigations with different optical set-up's and cameras. Should be in the solar threads somewhere...

I occasionally have issues with my DMK21....

[sheri_barri]

Very nice mosaic. The flat field theory looks to have worked very well.

[markt]

Thanks all, next step in the experiment is to add a dark frame when imaging too...